Canine deep mycosis

Deep mycosis is an infection caused by fungi that invade the skin, mucosa and viscera. There are many kinds of pathogens. These pathogens are widely found in soil, animal feces and milk. Dogs are infected mainly through contact with contaminated soil or through respiratory tract and digestive tract, and only a few fungi are contagious. Deep mycosis can occur in various organs of the body, which is characterized by granulomatous inflammation, necrosis, abscess, ulcer, impotence tube, connective tissue hyperplasia and nodule formation. The extensive addition of antibiotics in feed may be an important cause of deep mycosis in dogs.

Several major deep mycosis in dogs are as follows:

1. Histoplasmosis

The pathogen is histoplasmosis capsular. Growing in the soil, mainly through respiratory tract infection, the sick dog mainly showed persistent, difficult to cure intractable cough and diarrhea, no sputum excretion. Sick dogs anorexia, weight loss, irregular fever, vomiting, dermatitis, abdominal wall palpation can often find enlarged mesenteric lymph nodes. Chronic cases sometimes show ulceration of buccal mucosa and enlargement of tonsils.

When it is clinically found that dogs show intractable cough or diarrhea, the disease should be considered. If possible, intradermal test should be done with capsular histoplasmin, and diagnosis can also be made by chest X-ray, serum complement fixation test, Agar diffusion test and so on.

Amphotericin B has a good effect on the disease, with a total dosage of 4 mg / kg body weight, divided into 10 times, injected once every two days, dissolved in water for injection before use, and then diluted to 0.1% (mg) with glucose saline before intravenous injection. The total amount should not exceed 5 mg / kg body weight, otherwise it can damage the kidneys. Clotrimazole (antifungal No. 1) also has a good effect on the disease, with a dose of 0.75 ~ 1.5 grams, orally taken twice.

2. Coccidiomycosis

The pathogen is coccidiomycetes. Mainly through the respiratory tract infection. Granuloma occurs in the lungs and bronchial or mediastinal lymph nodes of the diseased dogs. the diseased dog presents with elevated body temperature, cough, dyspnea, loss of appetite, weight loss and diarrhea. When it invades the joint, it shows claudication and muscle atrophy.

The disease spreads rapidly among dogs. When suspicious symptoms occur in dogs, further chest X-ray should be taken, and coccidioidin intradermal test and serum complement fixation test should be done when possible.

The treatment is the same as histoplasmosis.

3. Blastomycosis

The pathogen is Blastomyces dermatitis.

The disease can be divided into two types: systemic type and skin type. The main manifestations of systemic type are lung disease, depression, fever, anorexia, emaciation and cough in sick dogs. During the autopsy of the dead dog, there were nodules and abscesses in all lobes of the lungs, the lungs showed grayish white or reddish markings, and focal or diffuse hardening. The center of the granulomatous nodule is necrotic, but not calcified. When the lesion spreads around, it can make bronchial and mediastinal lymph nodes enlarged, suppurate, and even cause pleurisy. Cutaneous blastomycosis is characterized by solitary or multiple skin granulomas, followed by liquefaction and necrosis in the center and ulcers.

The chest X-ray shows that there are no calcified nodules or hardening of the lungs, which is helpful for the diagnosis of the disease. It is best to do a biopsy of skin nodules. When microscopic examination from pus and sputum shows that there are single or budding spherical cells and the cell wall is thick and refractive (double-layer outline), the diagnosis can be made. Once the disease spreads, it is difficult to cure. Amphotericin B can be used in the early stage. Surgical removal of skin nodules can be performed.

4. Cryptococcosis

The pathogen is Cryptococcus neoformans. It exists in soil and can be separated from soil, bird dung, fruit and milk.

Cryptobulbar scissors disease mainly affects the brain, meninges, paranasal sinuses and lungs, spleen, muscles, joints, skin and other parts, causing movement disorders, circle movement, abnormal behavior, lameness, hypersensitivity and rhinorrhea. At the time of autopsy, there were small suppurative foci in the paranasal sinus, turbinate bone, nasal cavity and brain, and mucopulent inflammation in the meninges. Subcutaneous granuloma can be seen in the ears, eyes and feet.

The possibility of cryptococcosis should be considered when unexplained respiratory and central nervous system symptoms are found in diseased dogs. Further pathogen examination, serological test and histopathological examination will contribute to the diagnosis of the disease.

The treatment is the same as histoplasmosis.

5. Sporomycosis

The pathogen is Sporothrix schenckii, which is infected by trauma.

The lesions mainly invade the skin, often occur in the extremities, and spread along the lymphatic vessels, forming a typical banded swelling. The primary site is a solid, inelastic, movable, non-tenderness nodule or granuloma, the nodule is backward by hair, it can be seen with exudate, form a scab after drying up, and some nodules can form abscess and ulcer after ulceration.

According to the above symptoms, it can be suspected to be the disease. In order to make a diagnosis, the disease materials can be taken from the unbroken abscess for isolation and culture. if the pathogenic bacteria are isolated, the diagnosis can be made.

Iodide has a special effect on the disease. Potassium iodide can be taken orally with a daily dose of 4.4 mg / kg body weight. Sodium iodide can also be injected intravenously. Oral griseofulvin was given at a dose of 20 mg / kg body weight per day for 2 weeks. Skin ulcers can be warmed with 0.2% iodine solution (plus 2% potassium iodide). Local application of 5-10% potassium iodide ointment can often get a good effect.

6. Candidiasis (thrush)

The pathogen is Candida albicans. It is often found in the digestive tract of healthy animals. Young and frail, especially animals fed with antibacterial additives or treated with antibiotics for a long time, are prone to infection.

The clinical feature of the diseased dog is the formation of a large or several small raised soft spots on the oral and esophageal mucosa, which are covered with a yellow-white pseudomembrane and are prone to bleeding after peeling off.

For the diseased dogs with the above symptoms, the specimens were scraped from the mucous membrane and skin lesions for microscopic examination. If yeast cells and entangled filaments were found, the diagnosis could be made.

Early detection and early treatment are of great significance to improve the curative effect, and the treatment can refer to histoplasmosis. In order to prevent the disease, the most important thing is to remove all kinds of inducements, and those who use antibacterial additives for a long time should stop feeding. Anti-seedling agents that have been used for too long should also be stopped to avoid the growth of Candida albicans. Nystatin can also be taken orally from time to time at a dose of 600000 ~ 1 million units per day for 5 consecutive days.